Patent GB-927046-A (GB)
Title: Foamed rubber or synthetic resin based compositions and articles and method for the preparation thereof
IPC: C08J9/30
Filed: 1960-03-15
Abstract: Cellular articles are produced by drying stable self-supporting foam compositions which are prepared by introducing and mixing particulate solids into an aqueous dispersion of a rubbery or synthetic resin binder through the gas-liquid interface thereof to entrain air in the dispersion, the solids being the essential airentraining means and being added in an amount effective to form a self-supporting foamed binder dispersion, this amount being at least equal in quantity to the binder solids.  Specified binders include natural rubber, the synthetic rubbers such as polybutadiene-1,3, copolymers of butadiene-1,3 and styrene, copolymers of butadiene and acrylonitrile, poly-(2-chloro-buta-diene-1,3), polyisobutylene, polyisoprene, polysulphide polymers, polyacrylates, butadieneacrylonitrile-methacrylic acid copolymers, phenol-, urea- and melamine-aldehyde resins and vinyl acetate and alcohol polymers and copolymers.  Scrap rubber particles are the preferred particulate solids but there are also mentioned particles of ethyl cellulose, sawdust, polystyrene, phenol-, urea- and melamine-aldehyde resins and polyacrylates.  The binder dispersion may contain a protective or lyophilic colloid such as casein; mucilages of plant origin such as guar bean, locust bean and linseed; natural gums, gum tragacanth, gum arabic, karaya gum, gum ghatti, carrage enin, agar, alginates and the pertosan type of grains; and synthetic gums such as the carboxyethers of cellulae and the alkali metal polyacrylates.  In Example (1), rubber dust is gradually added to a compounded latex containing butadiene-styrene latex, zinc diethyl dithiocarbamate, zinc salt of 2-mercapto benzothiazole, zinc oxide, sulphur, casein, sodium salt of a disproportionated resin acid, process oil, polyalkyl polyphenol and whiting.  In the other examples, (2) an acid carboxylic butadiene-acrylonitrile latex is used, (3) granulated ethyl cellulose is the particulate solid, (4) an additional blowing agent is utilized and (5) Karaya gum or sodium polyacrylate replaces the casein of Example (1).ALSO:Cellular articles are produced by drying stable self-supporting foam compositions which are prepared by introducing and mixing particulate solids into an aqueous dispersion of a rubbery or synthetic resin binder through the gas-liquid interface thereof to entrain air in the dispersion, the solids being the essential air-entraining means and being added in an amount effective to form a self-supporting foamed binder dispersion, this amount being at least equal in quantity to the binder solids.  Specified binders include natural rubber, the synthetic rubbers such as polybutadiene-1, 3, copolymers of butadiene-1, 3 and styrene, copolymers of butadiene and acrylonitrile, poly- (2-chloro-butadiene-1, 3), polyisobutylene, polyisoprene, polysulphide polymers, polyacrylates, butadiene-acrylonitrile-methacrylic acid copolymers, phenol-, urea- and melamine-aldehyde resins and vinyl acetate and alcohol polymers and copolymers.  Scrap rubber particles are the preferred particulate solids but there are also specified particles of ethyl cellulose, sawdust, polystyrene, phenol-, urea and melamine-aldehyde resins and polyacrylates.  The binder dispersion may contain a protective or lyophilic colloid, e.g. casein; mucilages of plant origin such as guar bean, locust bean and linseed; natural gums such as gum tragacanth, gum arabic, karaya gum, gum ghatti, carrageenim, agar, alginates and the pentosan type of grains; and synthetic gums such as the carboxyethers of cellulose and the alkali metal polyacrylates. In example (1), rubber dust is gradually added to a compounded latex containing butadiene-styrene latex, zinc diethyl dithiocarbonate, p zinc salt of 2-mercapto benzothiazole, zinc oxide, sulphur, casein, sodium salt of a disproportionated resin acid, process oil, polyalkyl polyphenol and whiting.  In the other examples, (2) an acid carboxylic butadiene-acrylonitrile latex is used (3) granulated ethyl cellulose is the particulate solids (4) an additional blowing agent, N, N1-dinitroso pentamethylene tetramine, is utilised and (5) karaya gum or sodium polyacrylate replaces the casein of example (1).